This invention relates to a medical diagnostic ultrasound system and method for vessel structure analysis.
Accurate diagnosis of constrictions in vessels, such as the carotid artery, assists medical treatment. Two or three-dimensional ultrasound images of the carotid are rendered from blood flow information. The user subjectively examines the geometry of the rendering for any constriction. This examination typically requires skill and experience to distinguish an actual stenosis from an image artifact or other natural vessel variations.
The present invention is defined by the following claims, and nothing in this section should be taken as a limitation on those claims. By way of introduction, the preferred embodiment described below includes a method and system for automated vessel structure analysis. Where the vessel bifurcates, such as the carotid artery, the common portion (i.e. the bifurcation bulb) is divided between the branches. For example, the common portion is divided as a function of a ratio of (1) the integral of ultrasound flow data at a cross-section of a first branch to (2) the integral of ultrasound flow data at a cross-section of a second branch. As another example, the intersection of planes perpendicular to the center axis of each branch within the common area divides the common portion. The ultrasound data representing the common portion is associated with each branch as a function of the division. This association assists with flow and structural analysis.
For use with the bifurcation division discussed above or for other vessels, a method and system for automatically assigning a center (i.e. medial) axis of the vessel is provided. A center of flow for the vessel is determined, such as by: (1) calculating gradient values from ultrasound data representing flow in the vessel, (2) determining a magnitude of the gradient values for each spatial location, and (3) reducing a boundary of the vessel by an amount that is a function of the magnitude of the ultrasound data until a center of flow (i.e. line) is identified. The center of flow is assigned as the center of the axis. The determined center axis is used to identify constrictions or analyze flow for medical diagnosis.
A memory and processor is provided for automatically performing the acts discussed above. Minimal user input allows the ultrasound system to automatically provide information assisting medical diagnosis.
Further aspects and advantages of the invention are discussed below in conjunction with the preferred embodiments.